What I know about Cloud Computing

I’ve got a simple explanation: Data storage is really, really inexpensive, and the price keeps going down. Why would I take the risk of storing my most important data somewhere with uncontrolled security (might be great security, but I’m not in control of it), when I can store 1TB of data for about $100 investment.

Am I missing something else? I don’t see a benefit that justifies the risk.